What Fatigue Really Is – And 3 Ways To Conquer It!

“Who needs this?”

Said Joe DeSena, founder of The Spartan Race, as he was in the middle of doing an Ironman Triathlon in Utah. Joe is renowned for pushing his body to the limit, but this time he felt like he had pushed his body as far as it could possibly go. He was 10 miles into the run and he was so nauseous that he had to walk over to an ambulance to vomit uncontrollably. 

Joe had all but decided that he was going to amongst those on the DNF (did not finish) list, when he saw a woman with one leg run by him. When he saw the woman pushing herself through a physical feat that many 2-legged people don’t even try, it changed his perspective. Seeing this gave him the strength he needed to run with her for the final 16 miles and finish the race! [1]


To say that Joe was fatigued would be an understatement. His body and mind were telling him that he had finally reached his limit. Yet, all it took was a change in perspective from a focus on himself and his problems, to the one-legged woman who was going to triumph over circumstance to complete one of the world’s hardest competitions.

Once Joe was able to believe that if she could get it done, then he could to, his body was able to follow his mental desire 16 miles to the finish line. This begs the question, was Joe really fatigued? 


Physiologists used to believe that when our bodies give up, it is because they scientifically cannot go any farther. Fatigue, they thought, is what occurs when the muscles in our bodies cannot keep working until they replenish their energy through adequate rest and nutrition. This makes sense in theory, but they could never actually prove that that is what made exercisers actually give up

There was one physiologist, however, who did not believe that this was the case. In 1924, Archibald Hill proposed the idea that when the body is working hard and depleting its energy, the brain will begin to send messages to the muscles to slow down [2]. The brain does this to conserve energy and survive the many hardships we humans used to have to deal with. If Hill was right about this, then our physical limits would be well beyond what we believe them to be.


Following this research, a modern day ultra marathoner and sports scientist named Timothy Noakes began testing this theory. He found that the brain was indeed sending messages to the body to “STOP!” when it sensed rapidly depleting energy stores [3]. This message is what we feel when we get fatigued. So the brain will create this sense of fatigue that has very little to do with the actual muscles ability to continue to work.

Noakes’ research indicates that fatigue is not muscle failure at all, but rather should be classified as an emotion like fear or anxiety. It’s simply another message that the brain sends throughout the body that attempts to keep us safe from danger. And just like with fear and anxiety, we don’t have to act on the brain’s message. We can keep pushing our bodies beyond fatigue the same way we can summon the courage to give a public speech or ask that person we have a crush on for a date. 


Now that we know that fatigue is not exhaustion, does that mean that we can trick the brain to never feel fatigue anymore? Unfortunately no. No matter what, we will still feel the effects of fatigue the same way we will always have things that trigger fear and anxiety.

However there are tactics that we can use to fight against fatigue:

1.    Remember what’s happening

When the feeling of fatigue hits, simply remember that fatigue is not exhaustion. Remind yourself that your body is still strong and empower yourself to keep going. That simple reminder will send a message back to the brain that you are not in any real danger and decrease your feeling of fatigue. [4]

2.    Use the “chunking” technique

If you are on mile 1 of a 7 mile run and starting to feel fatigued, your brain will send even more messages to your body to “STOP”. It will do this because it knows how much farther you need to go. Instead, use the chunking technique to focus your mind on simply getting through the next mile. If your brain is focused on what it believes it can accomplish, it will lower the amount of fatigue in your body. [5]

3.    Find inspiration

Joe DeSena was able to finish the Utah Ironman because the one-legged woman running by inspired him. It took his mind off of his own body and onto the sheer determination she had to overcome her physical obstacles. When you’re feeling fatigued, find your source of inspiration that will keep you strong. [6]

Remember why you are doing what you are doing and believe in yourself. This will focus your mind on the thing you’re fighting for, rather than the pain you’re feeling, which will lower your fatigue. 


At some point, every single one of us has experienced fatigue. Until recently, we as a society have taken that fatigue to mean that we cannot physically continue. Now we know that this is not the case. Fatigue is not a physiological reaction to physical exertion, it is an emotional response to help us conserve energy resources.

This is why we hear incredible stories about people like Joe DeSena pushing themselves beyond their previous limitations. The next time your mind tries to tell your body that you’re fatigued, remember what’s happening, focus on what you can accomplish and find your inspiration to keep going. You have no idea what your real limits are!


  1. Helm, Burt. "Joe De Sena's Spartan Empire." Mensjournal.com. N.p., 21 Apr. 2014. Web.
  2. Hill, A. V., C. N. H. Long, and H. Lupton. "Muscular Exercise, Lactic Acid, and the Supply and Utilisation of Oxygen." Proceedings of the Royal Society B: Biological Sciences 96.679 (1924): 438-75. Web.
  3. Noakes, T. D. "From Catastrophe to Complexity: A Novel Model of Integrative Central Neural Regulation of Effort and Fatigue during Exercise in Humans: Summary and Conclusions." British Journal of Sports Medicine 39.2 (2005): 120-24. Web.
  4. Job, V., C. S. Dweck, and G. M. Walton. "Ego Depletion--Is It All in Your Head?: Implicit Theories About Willpower Affect Self-Regulation." Psychological Science 21.11 (2010): 1686-693. Web.
  5. Baumeister, Roy F., and John Tierney. Willpower: Rediscovering the Greatest Human Strength. New York: Penguin, 2011.
  6. Muraven, Mark, and Elisaveta Slessareva. "Mechanisms of Self-Control Failure: Motivation and Limited Resources." Personality and Social Psychology Bulletin 29.7 (2003): 894-906.